Update DebugInfo interface to use metadata, instead of special named llvm.dbg.... global variables, to encode debugging information in llvm IR. This is mostly a mechanical change that tests metadata support very well.

This change speeds up llvm-gcc by more then 6% at "-O0 -g" (measured by compiling InstructionCombining.cpp!)

llvm-svn: 79977
diff --git a/llvm/lib/Target/PIC16/PIC16DebugInfo.h b/llvm/lib/Target/PIC16/PIC16DebugInfo.h
index 2ccaba3..54e27c7 100644
--- a/llvm/lib/Target/PIC16/PIC16DebugInfo.h
+++ b/llvm/lib/Target/PIC16/PIC16DebugInfo.h
@@ -117,7 +117,7 @@
 
 
     private:
-    void SwitchToCU (GlobalVariable *CU);
+    void SwitchToCU (MDNode *CU);
     void SwitchToLine (unsigned Line, bool IsInBeginFunction = false);
 
     void PopulateDebugInfo (DIType Ty, unsigned short &TypeNo, bool &HasAux,